1. Field of the Invention
The present invention relates to a holder device for movably holding a recording sheet roll.
2. Description Related to the Prior Art
For a photographic printer and a color thermal printer, a recording sheet roll is used and cut into a sheet in predetermined sizes after printing. The recording sheet roll has a long recording sheet wound about a hollow core made of paper or plastic.
In order to mount the recording sheet roll in a feeding part of the printer, a holder device for a recording sheet roll, composed of a pair of holders, is set to both ends of the recording sheet roll. A pair of support members is fixed in the feeding part of the printer for supporting each holder, to which the recording sheet roll is mounted. The recording sheet roll is rotatably held by each holder, which is set in slits formed on the support members. In detail, each holder is composed of a fitting part to fit into the internal circumference of the core, a flange to press the lateral end of the recording sheet roll, and a shaft, that is inserted into the slits to rotatably hold the recording sheet roll. A positioning groove to fit the slits of the support member is provided in the shaft to decide the position of the recording sheet roll in the widthwise direction.
A variety of recording sheet are provided, and they often have different widths. The positioning groove and the slit do not meet each other if the width of the recording sheet roll is changed, since the distance between the holders are changed accordingly. Measures taken against such problem include using plural holders corresponding to the various widths of the recording sheet rolls. Alternatively, Japanese Patent Laid-Open Publication Number H7-223759 discloses a spacer that fits into the core of the recording sheet roll. By applying and removing the spacer, the holder may correspond to plural types of recording sheet rolls with different widths.
However, it is inconvenient for a user to select the right holder or the right spacer among plural holders or spacers in accordance with the width of the recording sheet roll. In addition, if the user makes a wrong choice of the holder or the spacer, the user is required to remove the holder or the spacer from the recording sheet roll and to attach the right holder or the right spacer, and that is a burden for the user.
An object of the present invention is to provide a holder device to which plural recording sheet rolls with different widths are easily mounted.
In order to achieve the above object, the holder device for holding a recording sheet roll comprises a first and a second holder members supported by a pair of support members, the first holder member has a first fitting part for one end of the recording sheet roll and a first shaft to rotatably support the first fitting part. On the first shaft, plural positioning grooves along the direction of the rotation axis of the first fitting part. One of the positioning grooves is fit into the support member in accordance with the width of the recording sheet roll.
The second holder member has a second fitting part fitted into the other end of the recording sheet roll, and a second shaft to rotatably support the second fitting part. One engaging groove is formed on the second shaft to fit into the support member. The second shaft is shiftable between a first position and a second position. At the first position, the engaging groove is the farthest from the fitting part. The engaging groove is the nearest to the fitting part at the second position. The second shaft to engage with the support member gets closer to the second position as the recording sheet roll becomes wider.
The second shaft has a substantially conical-shaped guide part that is pressed by the support member to shift the second shaft toward the second position. The second shaft may be biased toward the first position by an elastic member provided between the second fitting part and the second shaft. In order to facilitate attachment of the holder members to the support members, the positioning groove and the engaging groove are different in depth.
In the preferred embodiment, two positioning grooves are formed on the first shaft to selectively support a narrow recording sheet roll and a wide recording sheet roll. The second shaft is located at the first position when the narrow recording sheet roll is attached to the holder members, while the second shaft is at the second position when the wide recording sheet roll is attached.